In this quick Arduino tutorial I will explain how you can control a relay using the Arduino Board, one 1K and one 10K resistors, 1 BC547 transistor, one 6V or 12V relay, one 1N4007 diode and a 12V fan ...

relay-controller.ino is Arduino firmware for a computer interface for up to three latching relays. Protocol. The protocol really ought to be replaced, perhaps with a standard industrial automation ...